Objective To analyze the computed tomography (CT) imaging features of urachal carcinoma and evaluate its diagnostic value. Methods The clinical data of 20 patients with urachal carcinoma confirmed by surgery and pathology, who were admitted to The First Affiliated Hospital of Naval Medical University from Dec. 2012 to Dec. 2022, were collected. Seventeen of the 20 patients underwent enhanced CT urography and 3 underwent pelvic CT plain scan＋enhanced scan. After scanning, multiplanar reconstruction was performed on the post-processing workstation. The general data, clinical symptoms, CT imaging findings, pathological data, and prognosis of the patients were analyzed and summarized. Results The patients included 16 males and 4 females, aged 27 to 75 years old, with a median age of 61.50 (41.50, 71.25) years old. The tumors were all located in the anterior wall of the bladder, along the urachus, with a maximum diameter of 1.72-5.55 cm and a median maximum diameter of 3.34 (2.48, 3.71) cm. Fourteen cases had cystic-solid lesions and 6 had solid lesions. In the cystic-solid lesions, 9 cases showed the “upper cystic and lower solid” sign on the sagittal plane. Calcification was noted in 17 cases. After enhanced scanning, 18 cases showed progressive enhancement, and 2 cases showed “fast in and fast out” enhancement. Tumor invasion extended beyond the urachus and/or bladder muscle layer in 19 cases. At the end of follow-up, 3 cases had recurrence, 2 had metastasis, 5 had no recurrence after surgery, 3 died, and 7 were lost to follow-up. Conclusion Urachal carcinoma has certain characteristic manifestations on CT imaging. Reconstructing the sagittal plane with enhanced CT scanning and multiplanner reformation can help preoperative diagnosis and prognostic evaluation of urachal carcinoma.